A user may have multiple accounts storing private data. For instance, the user may have an online banking account, a social networking account, an email account, a medical account, and an online store account.
When accessing an account, a user may have to respond to a Turing test, e.g., a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) test. For instance, a server of the account may require the user to enter a user name, password, and a CAPTCHA response of a CAPTCHA challenge, e.g., a phrase including wavy characters.